In general, video codecs are similarly structured, but the detailed process for each structure is different from one another. Due to these differences, it is quite difficult to unify different codecs.
FIG. 1 shows a typical process of a unified codec based on the conventional art. FIG. 1 illustrates the operational principle of a typical intra-only unified codec, focused on MPEG-2, MPEG-4, and AVC Intra coding.
Referring to FIG. 1, the functional process consists of, in the sequential order, parsing and entropy decoding S100, data-reordering S110, inverse scan S120, inverse DC/AC prediction S130, inverse quantization S140, inverse transform S150, inverse intra-prediction S160, memory for decoded samples S170, and deblocking-filter S180. As described above, the conventional art is simply divided by the function or the order of process, and each step is structured to process in detail according to the codec, resulting in a large portion of redundant process steps.
Moreover, while a clear distinction between a common component (e.g., process, function, etc.) and a separate component is a prerequisite for unifying codecs, it is difficult to distinguish the similarities and differences in the structure of codecs based on the conventional art.
Furthermore, since no other unified codec than the structure based on aforementioned embodiment is suggested, aforementioned structure has to be so far used to unify codecs.